Journal of Thermal Analysis and Calorimetry

, Volume 123, Issue 3, pp 2599–2610 | Cite as

Approximation-based integral versus differential isoconversional approaches to the evaluation of kinetic parameters from thermogravimetry

kinetic analysis of the dehydration of a pharmaceutical hydrate
  • R. Neglur
  • D. Grooff
  • E. Hosten
  • M. Aucamp
  • W. Liebenberg


The relative accuracies of approximation-based integral versus differential isoconversional approaches for ‘actual’ E determination were investigated on experimental dehydration data of roxithromycin monohydrate from thermogravimetric (TG) analysis. The dehydration kinetic parameters and the relationship to the structural characteristics of the monohydrate and anhydrate forms from differential scanning calorimetry (DSC) and single-crystal X-ray diffractometry (SC-XRD) are also reported. Integral methods versus the differential Friedman isoconversional method evaluated E correspondences in both iso- and non-isothermal TG methods. The reliability in E from Friedman approached that of estimates from current most accepted integral isoconversional methods and was even superior to methods (for non-isothermal studies) that employ an approximation to the temperature integral (modified Kissinger–Akahira–Sunose, Senum–Yang fourth degree). Structural characterization (DSC, SC-XRD) and kinetic analysis from generalized kinetic master plots concluded that coordinated water occupied interlinked voids in crystal structure which may have facilitated the multidimensional diffusional loss of water upon heating without disruption of the crystal structure.


Roxithromycin Solid-state kinetics Advanced isoconversional Differential Friedman 



The authors acknowledge the Nelson Mandela Metropolitan University (NMMU) and National Research Foundation (NRF) for research funding.

Supplementary material

10973_2016_5244_MOESM1_ESM.pdf (173 kb)
Supplementary material 1 (PDF 173 kb)
10973_2016_5244_MOESM2_ESM.pdf (174 kb)
Supplementary material 2 (PDF 173 kb)


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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2016

Authors and Affiliations

  • R. Neglur
    • 1
  • D. Grooff
    • 1
  • E. Hosten
    • 1
  • M. Aucamp
    • 2
  • W. Liebenberg
    • 2
  1. 1.Department of ChemistryNelson Mandela Metropolitan UniversityPort ElizabethSouth Africa
  2. 2.Center of Excellence for Pharmaceutical Sciences, Faculty of Health SciencesNorth-West UniversityPotchefstroomSouth Africa

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